1. Field of the Invention
The present invention relates to a heat sink-integrated double-sided cooled power module, and more particularly, to a power module for an inverter that is used in an eco-friendly vehicle, such as a hybrid vehicle, an electrical vehicle, or a fuel cell vehicle.
2. Description of the Related Art
In general, a permanent magnet type motor is used as a driving mechanism in an electrical vehicle, a hybrid vehicle, or a fuel cell vehicle. The motor is typically driven by a phase current that is transmitted by an inverter that transforms a direct current (DC) voltage into a three-phase voltage due to a pulse width modulation (PWM) signal of a controller, via a power cable.
A power module that supplies power for driving the motor by receiving DC power from a battery, is combined with the inverter. The power module generally has a shape in which six or three phases are integrated as one package. Heat is generated in such a power module as a result of supplying power. Thus, various units for cooling heat generated in the power module are used for a stable operation of the power module. For example, a heat sink for reducing heat generated in an insulated-gate bipolar transistor (IGBT) and a diode chip when a switching operation is performed, is typically used in the power module. [NOTE: We would recommend including these in an IDS rather than the background.]
FIG. 1 is a cross-sectional view of a single-sided direct cooled power module according to the related art. As illustrated in FIG. 1, a case type single-sided direct cooling method is used in cooling the power module, and the power module is disposed on an integrated blazing heat sink. Here, reference numerals 100, 110, 120, and 130 represent a chip, a direct bonding material (DBM), a heat sink, and a solder, respectively.
Direct bonding copper (DBC) or direct bonding aluminum (DBA) is usually used as the DBM. However, in the power module illustrated in FIG. 1, it is difficult to manufacture the integrated blazing heat sink, and high manufacturing costs are required, and it is difficult to manage a plan view of the heat sink, however. Also, cooling efficiency of the power module is lowered compared to double-sided cooling.
FIG. 2 is a cross-sectional view of a double-sided indirect cooled power module according to the related art. As illustrated in FIG. 2, a double-sided indirect cooling method is used in cooling the power module, and thermal grease is applied onto both sides of the power module and then ceramics are attached to the power module so that both sides of the power module can be cooled by a heat sink. Here, reference numerals 100, 120, 130, 140, 150, 160, and 170 represent a chip, a heat sink, a solder, thermal grease, ceramics, a heat spreader, and a mold, respectively.
However, in the power module illustrated in FIG. 2, it is difficult to dispose both sides of each of several power modules parallel to each other so as to cool the power module by using the heat sink. Also, since the power module, the ceramics, and the heat sink are separate elements, it is difficult to create an inverter that combines the elements, since assembling thereof is complicated and thus, management and manufacturing thereof is difficult. Also, since the indirect cooling method is used in cooling the power module of FIG. 2, cooling efficiency is lowered compared to double-sided direct cooling.
FIG. 3 is a cross-sectional view of a double-sided direct cooled power module according to the related art. As illustrated in FIG. 3, a mold type double-sided direct cooling method is used in cooling the power module, and an insulation sheet is attached to both sides of the power module so that the power module can be fixed to a box type heat sink. Here, reference numerals 100, 120, 130, 160, 170, and 180 represent a chip, a heat sink, a solder, a heat spreader, a mold, and an insulation sheet, respectively.
However, in the power module of FIG. 3, the box type heat sink is combined with the power module by attaching the insulation sheet to the power module. In this case, cooling efficiency is lowered due to the insulation sheet. Also, when the insulation sheet is forcibly attached to the power module, the insulation sheet may become detached from the power module. In this case, a problem relating to insulation may occur.